Israeli security forces continued their search for saboteurs who blew up an oil pipeline near the Haifa refineries yesterday. It was the first Arab strike at a major industrial target inside Israel since the June, 1967 war and two Arab guerrilla organizations claimed credit for it. Police rounded up 169 suspects yesterday for questioning but later released all but 55 of them. A single stick of dynamite was found on the sandy stretch spanned by the pipelines which link the oil refineries with the fuel jetty in Haifa port, five miles away.

Police said footprints were found indicating that the explosives were planted by one man. They said the saboteur may have been brought to the area by car and are checking on vehicles seen in the area. Roadblocks and checkpoints have been set up on the approaches to Haifa and in other parts of the country.

The loss of fuel oil–about 1,000 tons valued at $55,000 poured into the Kishon River after the blast–is negligible. Neither Israel’s domestic fuel supply nor its petroleum exports were affected. The oil carried by the damaged 12-inch pipe was for bunkering ships calling at Haifa port. The pipes are expected to be repaired and in service by tomorrow.

The psychological impact of the act far exceeded the damage done. The Haifa refineries, the center of Israel’s growing petrochemical industry, is one of the most heavily guarded areas in the country. It is located far from the borders–some 12 miles south of the Lebanese frontier and about 30 miles west of the Jordanian line. Penetration of the area was a coup for the saboteurs. In Cairo and Beirut today El Fatah spokesmen claimed that their forces had carried out the mission. That claim was disputed in Amman where the Popular Front for the Liberation of Palestine alleged that their commandos did the job.

Observers here said the sabotage of the pipelines may herald a change of tactics on the part of the Arab guerrillas whose targets here to fore have been civilian. The most recent was a narrow street leading to the Western Wall in Old Jerusalem where three 10-pound bombs exploded injuring six persons last Friday.